The present invention relates to a method and an arrangement for detection of short circuits in a vehicle. By means of the invention, short circuits in a vehicle can be detected in a simple and reliable way and can accordingly be remedied.
In modern vehicles, such as, for example, trucks, buses and construction vehicles, there is a very large amount of electrical cabling. Due to, for example, incorrect laying of cables and movements of the vehicle, the cables' insulation can be damaged, whereby short circuits can arise. These short circuits can be of short duration and intermittent, which means that the fuses in the vehicle are not able to react, which can be very trying and irritating for the driver of the vehicle. In addition, various electrical systems in the vehicle can be disturbed by a short circuit of short duration, with an error function as a result. For example, a processor in a control unit can restart when the supply voltage drops below a certain level.
To be able to detect short circuits in a vehicle reliably at an early stage is therefore an important function in a vehicle.
Document JP 11055848 describes an arrangement that is intended to detect short circuits in the electrical system in a car. A disadvantage of this arrangement is that it can only detect short circuits on the specific cable to which it is connected.
It is desirable to produce an arrangement and a method for being able to detect short circuits that are of short duration and/or intermittent in the electrical system in a vehicle, suitably a truck, at an early stage in a quick and reliable way.
In accordance with an aspect of the present invention, a method is provided for detection of short circuits in the electrical system in a vehicle provided with a battery. The method comprises measurement and storage of the value of the battery voltage at a first moment in time, measurement of the value of the battery voltage at a second moment in time, and comparison of the values of the battery voltage at the first and second moments in time.
If the battery voltages at the two moments in time differ from each other by more than a predetermined value, it is checked whether one or several of certain predefined systems in the vehicle have been engaged during the interval of time between the first and the second moments in time, with a short circuit being assumed to have occurred if none of the systems in the vehicle have been engaged during the interval of time.
In a further aspect of the invention, an arrangement for carrying out the method steps as described above is provided.
The method is suitably carried out continually while the vehicle is operation, and in the same way, an arrangement according to the invention can be running and carrying out measurements and comparisons continually while the vehicle is in operation.